Sand removing installation



P. DANEL SAND REMOVING INSTALLATION July 24, 1951 2 Sheets-Sheet l .N\ I ul I T TT TT I TTL w s Q u h Filed Feb. 19, 1948 ATTORNEYS P. DANEL SAND REMOVING INSTALLATION July 24, 1951 2 Sheets-Sheet 2 Filed Feb. 19, 1948 I N VENTOR 0 2 Z .J Tw

Patented July 24, 1951 SAND REMOVING INSTALLATION Pierre Danel, Grenoble,

Ateliers N eyret-Beylier & Piccard-Pictet, Grenoble, France, a corporation of France Application February 19, 1948, Serial No. 9,397 In France November 15, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires November 15, 1965 The present invention relates to an installation for removing sand, ilt and similar materials from water being led from water courses, reservoirs and the like to hydraulic installations such as hydro-electric power stations, irrigation works, water supply systems for cities, industrial plants, e

It i known to provide sand-remover installations of various types whereby the sand-laden water is led from the reservoir or water course through a channel having a section of decreased gradient as compared with the upper and lower reaches thereof or which is widened for a portion 'ofits length to decrease the flow velocity and permit thesettling of the sand from the passing stream. The settled sand is removed by intermittently or continuously drawing 01f a portion of the water from adjacent the lower portionof the channel that has become more heavily laden with thesettling sand. This results in the loss of a certain portion of the'available output of water which heretofore, even under the most favorable conditions, has amounted to about one-tenth of the total flow.

The present invention has for an object to bring about the settling of the sand and its removal while at the same time recovering for useful applications and witha minimum loss of head a greater portion of the water which is removed with the sand.

Other objects and advantages of the invention will appear as the description proceeds.

= According to the invention the sand-removing installation comprises a primary settling section of the main channel, which optionally may be divided into a plurality of parallelly-arranged channels, and which is provided with gates at the opposite ends for regulating the flow to a decreased velocity as compared with th entrance velocity so as to insure settling of the sand toward the bottom as the water passes therethrough. The clarified water is drawn off from the upper level of the passing stream and discharges to the downstream reach of the channel leading tothe intake of the power station or to another point of useful disposal. The sand settling to the bottom of the primary sand remover or settler is discharged in a partial flow of heavily charged water to a separat secondary settlin chamber where the water of the partial flow i allowed to become relatively quiescent with the result that the sand is substantially completely settled to the bottom of this second settling chamber or basin. The clarified portion of the-water drawn off into this secondar settler France, assignor to 13 Claims. (01. sic- 52) is returned to the main channel downstream from the primary settler. A minor portion of the originally heavily charged water drawn off into the second settler is utilized to flush out the sand collecting in the bottom of this settler. If desired and the volume of water being treated warrants such a step, the water used to evacuate the sand collecting at the bottom of the second settler may be passed to a third settling reservoir or basin where the decanting operation carried on in the second settler is repeated with. a still further recovery of clarified water.

The invention will now be further described by reference to the accompanying drawings wherein:

Fig; 1 is an elevational view with parts in section on the line A-A of Fig. 2 of one embodiment of the invention; a

Fig. 2 is a corresponding plan view; Fig. 3 is an elevationalview with parts in section taken on the line B-B of Fig 4 and illustrating another embodiment of the invention; and

Fig. 4 is a corresponding plan view;

Fig. 5 is a plan view of a modification of th embodiment of Figs. 1 and 2.

As shown in Figs. 1 and 2, a sand-removerof a known type constitutes the primary settling section of my device and is made up of a pair of parallelly-arranged settling or settlers I and 2 interposed in a channel 3 leading from the water reservoir 30 or another suitable source of water that is to be treated on its way to a point of utilization. The primary settlers l and 2 are separated by a dividing wall 4 and are respectively provided with inlet gates 5, B and outlet gates "I, 8 for controlling the flow to and from therespective primary settlers. The settlers l and 2am respectively provided wih solid material collecting channels 9 and Ill which are respectivelycon nected to a common discharge pipe I! by passages H and I2 controlled by gates-l5 and I6. Pas.- sages 3| and 32 controlled by gates l3 and [4 are also provided for directing a flow, if desired, directly from the respective settlers I and 2 at an intermediate level abov the channels 9 and 10 to the common discharge pipe 11. Individual sand-removers havin a structure similar to that above described are old in installations in which it has been customary to evacuate the settled solids in the form of a heavily loaded portion of the water through a discharge pipe to a suitable point of disposal.

According to the present invention, the pipe I! leads to a decanting reservoir or secondary settler l8 so disposed as to insurethat the freesunface of the water contained therein will normally stand at a level I9 whichis lower than the average level of the water in the primary settlers I and 2. A ShWI1.iI1Fig'..1, theibottom. of the decanting reservoir IBhasa steep: gradient to facilitate the flow of the'collecting solids to and their passage through a draw-off pipe 26 provided with; I

As the output an adjustable control valve M. to be treated in the decanting reservoir is relatively small as compared with the; total volume of water passed through theinstallation, the. di-- mensions of the reservoir I8 may be. relatively trolled soas to take place either continuously a'minor-flow or intermittently. In either case, the water Will -remain: within the reservoir l t asuilicient' length of time to: prevent eventhe finest" particles: of sand or silt to settle down to the bottom, andwhen the system is properly operated, the portion of the water standing in the upper part ofthe reservoir adjacent to the lower end thereof will be satisfactorily clarified and may be withdrawneither continuously or intermittently and discharged into the channel" 3 on-"tho downstream side of the settlers I- and 2 Asshown in Figs; l and 2- apump- 23 is provided for the purpose. It will be understood, however, that various other means for lifting the clarified waterfrom the reservoir Hi' to the channel 3' may be provided. For example, considering the low output required; a simple bucket conveyor may be employed, as illustrated at 36 in Fig. 5, and the power for operatingthe samemay be derived from the-water flowing directly from the' settlers I and 2 to the channel 3 by means" of a water Wheel 31 interposed" in the channel. v

The modificationshown in Figs. 3 and 4 is gen"- n a-lly similar to-that of- Figs. 1 and 2'. insofar as the primary-settlers are'concerned', but departs therefrom in providing an-arrangement' whereby the water recovered from the smaller partial "flow: passing through the secondary decanting reservoir or settler I8 is led directly into the main current of' clarified water passing through the downstrea-m 'part' oi thechannel .31with' a minimum loss of the availablehydraulic head.

According to this modification, the decanting reservoir IB" is positioned centrally in thechahnel 3 immediately downstream from the primary settlersfI and 2, thereby dividing this portion o1? thechannel 3 into side channels 24 and 25. In this: modification, the fiow of heavily charged 'water.from-the collecting channels I0 is led through: separate passages Fla and I'll) to the decanting reservoir or settler I8. The supplemental" higher level passages 3I and 32, controlled by the gates I3 and I4, also lead directly into. the secondary settler I8. The secondary settler I 8 is provided with a central collecting troughtt and relatively steeply inclined side walls which facilitate the flow of' the settling solids toward the collecting trough 33 whence they are withdrawn through a discharge pipe '20 under control of the'va1ve'2'I. The clarified water output from the secondary-settler I8 is discharged directly into the channel 3 by gravity. As shown in Fig. 3, the disposition of the secondary settler I8 is such that the water level therein. is normally maintainedat a height which is, approximately the same as; theheight of the water flowing through the side channels 24 and it 2.5 at the points where the flow from these channels debouches into the main downstream portion. at the: channel 3. As in the case of the modification of Figs. 1 and 2, the average level of the water in the primary settlers I and 2 is kept substantially higher than the water levelin the secondary settler I8. The maintenance of: the water levelin the settlers I and 2 is facilitated by providing raised sills 26 beneath the control gates i and 8. The smooth outflow of the clarified water from the settler I8 into the en di'of this settler.

flows from the side channels 24 and 25 at the point where they are reunited in the main channel 3 is assured by disposing the bottom 34 of the outlet. passagei'35 leading. fromxthe settler [81" atyapprox-imately the same.- leve'ka's: the bottom of. the channelyh at the point of discharge from the passage 35' into sucl'rachannel; and controlling the. velocity 'bysuitablyxrestricting thev side-walls: of the settler: adjacent the outlet and according to known hydraulic principles ln onder' to isolate the secondary settler I8 from the channelffi at. will; andiito. regulate th'e velocity of. flow of theaclarifiedi waterithereirom',

control gates-21: and; 2&mnunted1for movement about vertical; axes" are. providedyat thei outlet These gates; are? preferably so; disposed as to lie. flush with the; side: walls lot the settler: I18" whenithey are inifiullyiopenlpostvtion-v and to constitute smooth: continuations thereon h'suall'y,xtheyi are so. radiustednas to dimensions: that theymay meet: at aniacuter' angle when closed, thereby: minimizin the: opportunity for eddy: currents in: the. flow' from. theiside' cha n nels- 2'4! andi' into thermain channel 3.

' It 'will be: understood that.the provislonroi a plurality of: primary settlers I and. 2. with gate controls both at the upstream and. downstream ends thereof and: also: thes'provisionzot gatesil3,

I4', Ifi and: I '5:- leading therefrom tothe secondary settler It. or I8! insures a: wide; flexibility invthe operation ofrthe installation. For example; :dur'- ing low water: periods when. theamount of solids carried by the water is relatively. smalleonnil,

the partial flow from the lower porti'onsxof'the primary settlers to the secondary settler-may be closed off entirely orgreatlyreduced. Qptionally, under such circumstancesfit maybeqmore desirable; to: open the connections between the primary settlers: and the secondary settler; inter= mittentlyorperiodically to flush out-any-accumulated sand from the bottoms of" the-'primaryset tiers to the secondary settler. Similarly, it may be unnecessary to employ bothofthe' primary settlers-to handle the flow, and' in. this 'caseonl'y one of these elements need be'kept' in the citcuit, or they may be operated alternately as desired. Conversely, during periods of high water or even when an average output is-avaiI able, it may be more desirable to'operate-"the primarysettlers simultaneously with draw o'ff of settled solids to the secondary settler regu lated' to produce an optimumevacuation with the minimum amount ofwater required to'serv'e the-purpose. I I j It will be further understood that the invention makespossiblethe conservation of a-highpropo'ption of the available-energyof' the water. This i's an important consideration when the" water is destined for power generation. In this connection, it will be observed that the modification illustrated in Figs. 1 and 2 makes possible the recovery of a large proportion of the water here tofore lost in evacuating the solids without any necessary loss of energy whatsoever. Thisuis made possible because the energy required to raise the clarified water from the secondary settler or decanting reservoir [8 to the downstream continuation of the open channel may be supplied by the primary flow of clarified water from the primary settlers which maintains the same head irrespective of'the presence or absence of the second settler.

According to the embodiment of Figs. 3 and 4, the level of the water in the primary settlers is maintained somewhat higher thanin the primary greater loss of head between the primary settler and the level maintained in the downstream continuation of the open channel, this loss is compensated by the increased recovery of water which is discharged through the secondary settler into the main downstream flow.

It will be understood that the invention is not restricted to the particular embodiment described and that it is not to be deemed as limited otherwise than as indicated by the language of the appended claims.

I claim:

1. An installation for removing sand from water being led in open channel flow to a hydraulic installation and increasing the proportion of water usable at such installation, comprising a primary sand-settler interposed in an open channel flow for promoting gravity separation of sand from water passing therethrough, a second sand settler in communication with said primary sand settler adjacent the bottom thereof and adapted to receive a flow of sand-laden water from the bottom portion of said primary settler, means for controlling discharge of ole-sanded water from said primary settler directly to the adjacent downstream section of said channel, means for discharging sand settling to the bottom of said second settler, and means for returning water collecting in the upper portion of said second settler to said channel at the downstream side of said primary settler.

2. An installation for removing sand from wa ter being led in open channel flow to a hydraulic installation and increasing the proportion of Water usable at such installation, comprising a plurality of primary sand settlers interposed in parallel relation in an open channel flow for promoting gravity separation of sand from water passing therethrough, a secondary sand settler, conduits connecting said secondary settler to said primary settlers adjacent the bottoms thereof, means for controlling the flow of sand laden water through said conduits, means for controlling discharge of de-sand-ed water from said primary settlers to an adjacent downstream section of said channel, means for discharging sand settlingto the bottom of said secondary settler, and means for returning water collecting in the upper portion of said secondary settler to said channel at the downstream side of said primary settlers.

3. A sand-removing installation according to claim 2 in which means is provided for selectively co'nnectingsaid' primary settlers with saidsecondary settler. i i 8 s4. A rsand-removing installation according to claim 2 in which means is provided for regulating the flow. of water to said primary settlers independently of one another. i i

5; A sand-removing installation according to claim 2 in which said secondary settler is positioned adjacent the downstream ends of a pair of primary settlers and intermediate a pair of passageways connecting said primary settlers with said downstream channel, and which said secondary settler is provided with a spillway sill adjacent the lower end thereof lying'in substantiallythe same plane "as the bottom of thedownstream channel and mergingtherewith.

6. A sandremoving installation according to claim 5 in which means is provided for regulating the level of the fl'owfrom said primary settlers in correlation to the level of the flow from said secondary settler to said downstream channel.

7. In installation for removing sand from water being led in open channel flow to a hydraulic installation and increasing the proportion of water usable at such installation, comprising a pair of primary sand settlers interposed in parallel relation in an open channel flow for promoting gravity separation of sand from water passing therethrough, a secondary sand settler positioned intermediate said primary settlers at the downstream ends thereoi, conduits connecting said secondary settler to said primary settlers adja-- cent the bottoms of said primary settlers, side channels connecting said primary settlers at the downstream ends thereof with a downstream continuation of the main channel, said secondary settler being provided with an overflow discharge channel at the lower end thereof in communication with said main channel and means for varying the width of said discharge channel and thereby regulating the velocity of the flow from said secondary settler to said main channel.

8. A sand-removing installation according to claim 7 in which said primary settlers are provided with raised sills at the downstream ends thereof and with gates cooperating therewith for regulating the flow of de-sanded water from said primary settlers to the downstream continuation of the main channel in correlation with the level of the flow from said secondary settler to said downstream channel.

9. Apparatus for removing sand from a flowing stream of water comprising a primary settling section receiving the entire flow of said stream, said primary settling section comprising at least one sand settler arranged to decrease the velocity of the water flowing therethrough and having at its downstream end an upper outlet for clear water and a lower outlet for mixed sand and water, a discharge channel receiving water from said upper outlet, and a secondary settling section receiving the flow of mixed sand and water from the lower outlet of said sand settler, said secondary settling section comprising a secondary sand settler having at its downstream end a lower outlet for mixed sand and water and an upper outlet for clear water, and means for conveying water from the upper outlet of said secondary settler to said discharge channel.

10. Apparatus for removing sand from water as defined in claim 9, in which the depth of said secondary settler increases in the downstream direction at a gradient substantially steeper than that of said one settler, and in which the lower 2 outlet of. the secondary settler" communicates with the lowest point therein. I I

11'. Apparatus: for" removing Sandi. from" water :as defined? in claim 9,.xinc'1udinga baffles .inz said secondary settlerinearf the inlet end" thereof: to suppress turbulence therein.

12-; Apparatus for; removing Sandi from water asidefined in claim 9,. including" a; supplementary outlet passage leading fromrsaid one settler: to saidiisecondary settler forsuppiying clear 'water thereto.

' 13. Apparatus forremoving'sandiromwater as definedin; claim. 9, in whichi saidi'outlet channel is at; a==higher 1eve1z than the. upper outlet of. said secondary settlensaidi means for conveying water from the upper outletofsaid:secondnsettier includes means. for lifting: thewater to said higher level; andtmeans for: operating the water liftingimeans by power derived? from} the stream flowing through-said outlet. channel.

PIERRE. DANEL.

' REFERENCES CITED Thefo'llowing references are of i'ec'ordin tfre 'fiie'of this patent! V PATENTS UNITED STATES Number Name I Date:

. 783,196 Hatschek .'.'Feb.'21, 1905 1,069;040 Steuer July 29,1913 1,337,279 Sensibar Apr. 1920 1,431,367 Buchi 'O.ct..10, 1922 FOREIGN PATENTS Number Country Date.

103,670 Great Britain Jan; 24;:1-918 107,121 Great Britain June. 21,1917 107,326 .Austria Sept. 26,1927 487,155 France M'ar.j18, 1920 47,217 Germany June-6',.:1889

Certificate of Correction Patent No. 2,561,847 July 24, 1951 PIERRE DANEL It is hereby certified that error appears in the printed specification of the above numbered patent requiring Correction as follows:

Column'Q, line 29, before or insert cells; line 38, for wih read with;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 29th day of January, A. D. 1952.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

